Electrothermal ignition device



May 1, 1922..

L. F. HOFFMAN ELECTROTHERMAL IGNITION DEVICE Filed Sept. 18, 1922 2 Sheets-Sheet l NVENTOR.

ATTORNEY.

May 1, 1923. v

, L. F. HOFFMAN ELECTROTHERMAL IGNITION'DEVICE Filed Sept. 18 1922 '2' Sheets-Sheet 2 1 Nl "EN TOR.

A m T T A Patented May 1, 19 23.

UNITED STATES A 1,453,4 1 PATENT OFFICE... '1

LEON r. Harman, or'manxnm, PENNSYLVANIA, ASSIGNOR TO cnrcaoo rnnu MATIC TOOL coMgAuY, or NEW YORK, n. Y., A coaronarxo v or- NEW.-J' ERSEY.

ELECTROTHERMAL IGNITION DEVICE.

Application filed September 1's, 1922. Serial No. assess.

To all whom it may concern: Be it known that I, LEON F. HOFFMAN,

citizen of the United States, residing at adapted for use with heavy oil engines, of

Franklin, in the county of Venango and State of Pennsylvania, have invente'lcertain new and useful Improvements in Electrothermal Ignition Devices, of which the following is a specification. The object, construction, application and utility of my improved electro-thermal ignition device are herein'set forth with sufficient clearness to enable others skilled in the arts to which .its construction and use respectively relate, to make and use the same.

My improved ignition device is especially that type which after being in operation for a short time ignite their charge by high compression and the high degree of heat of 'certain portions of the wall of the combustion chamber. are, however, necessary when star'tingrsuch engines and the object of this invention is, primarily, to supply such supplementary means.

The construction and application of my improved ignition device are clearly shown in the accompanying drawings in which:

Fig. 1 is a central, longitudinal section of my improved device.

Fi 2 is an elevation partly in central longitu inal section.

Fig. 3 is an elevation.

Fig. 4 shows said device applied to the combustion chamber of a well-known type of heavy oil engine.

Referring to said drawings, my improved ignition device comprises a spirally wound resister coil 1 which is coiled around an insulator core, which, as shown in the drawing for the purpose of ready assembly, consists of two alined sections 2 and 3. Passing centrally, longitudinally through said insulator is a conductor rod 4 which, at its projecting outer end is provided with locknuts 5 and 6, between which a suitable electrical conductor may be secured to supply current from any suitable source to the coils. The opposite, inner end of said conductor rod projects from said core 23. One end of the wire forming said resistor coil 1 is connected to said inner end of said conductor rod so as to supply current theretosee Fig. 1. Said coil 1 is enclosed within a tube 7 of suitable metal, as nickel alloy, and

Supplementary ignition means is held in position by that portion 8 of the organization'which is termed the tube-holder.

the co-operatively threaded element 11 which is termed the body, the inner end of which contacts with. the adjacent end of :aid tube, thus firmly securing same in posi- The outer end of said body 11 is formed into a socket for the reception ofan annular enlargement 12 of the insulating core. Said socket 12 is internally screw-threaded for the reception of a co-operatively, externallythreaded thimble 13, the inner end of which bears upon the outer face of said annular enlargement 12, thus firmly securing said'insulating core firin'ly in position. The inner end of said tube-holder is externally screwthreaded for insertion into a tapped hole through the wall of the combustion chamber 14 of an oil engine.

It has been previously pointed out that one end of the wire forming the resister coil 1 is connected to the inner end of the conductor rod 4. It is now-explained that the other end of said wire is connected to the body 11, thus grounding the coil through the engine.

When an electrical current 'is caused to flow through the resister 1 the same becomes incandescent, and the resulting heat-is imparted 'to the tube 7 causing it alsoto become incandescent; and thus suitably heated to ignite the fuel mixture in the combustion chamber of the engine in. which it is inserted.

I claim the following: 1

1. An electro-thermal ignition device for internal. combustion motors, comprising a tubular casing closed at its inner'end, a core of insulatin material extending centrally into said casing and provided with a spirally disposed groove upon its periphery, a resistor composed of spirally-wound wlre L for said casing and said core, and an electrical conductor extending through said core, to the inner end of which one end of said resistor is attached, the other end of said vided with an annular shoulder, a core of insulating material provided with a spirallyrooved periphery extending into said casing, a resistor carried by said insulator comprising a closely spirally-wound wire occupying the spiral grooves of said insulator, a holder for said tubular casing adapted to engage said annular shoulder, a tubular body through which said insulative core exmeager casing and said core in their proper relative positions, and an electrical conductor extending through said insulative core, said resistor having one of its ends connected to the inner end of said conductor, the other end of said resistor being connected to said holder and thus grounded, said holder being adapted for mounting said casing within the combustion chamber of an internal combustion engine.

In testimony whereof I aflix my signature in presence of two witnesses.

LEON F. HOFFMAN. 

